Up to this point I have stumbled my way through keeping my flathead running but it has continued to run rougher and rougher and seemingly richer and richer. Thought it was a bad power valve so I replaced them with new 4.5s with the correct shoulders. Running 49 jets in rebuilt Holley 94s with extended shafts. If I remember correctly my grandpa had the 1952 block rebuilt with .010 over pistons. It has a stock cam, Mallory DP distributor, Offenhauser super dual intake and lakes headers with baffles. It has an external full flow oiling system and holley electric fuel pump (w/ adjustable pressure valve). Could the adjustable lifters need to be adjusted? Timing? Basically looking for a grey beard that is in the area that would be interested in teaching me a few things on how to tune the motor up correctly. Reading only gets you so far, especially when books/internet contradict so often. Thanks, Fordman1 aka Brian Check out my build thread for more info if I left anything out. Also I hope this is in the right location!
Make sure your butterflies are seated correctly and not stuck open or bent, if they are too far open you will get unwanted fuel and that will cause that baby to run very rich and very sloppy.
All of the tuning has been done the the air cleaners off and utilizing a uni-sync. I will check the butterfly fit, but it was running great in the past. Thanks for the comments this far! Posted using the Full Custom H.A.M.B. App!
Are you using a fuel filter? It doesn't take much to foul the internal passages. I had to stop and field-strip and clean my carb on my way back from Vantage. It started to crap out again before I got back home. I've cleaned it out again after getting home, but I'm adding an inline filter as soon as I can. I didn't like cleaning it beside the road, but I found a $20 bill on the ground by the car. That made me feel a little better. Stan
Running retarded can mimic rich condition...put a timing light on there and see that the advance starts moving right off of idle and goes up fast. Some recent Mallorys come through with stiff springs and long curves, starting to advance too late and moving up slowly.
I've also learned dual point ign. require more service than most are ready for. Symptoms can throw you a curve as to what's actually going on. Two of my motors with Mallory dist. have been changed over to Pertronix. They work 10 times better and I still have the look. As Bruce mentioned, a proper advance curve is a must. The Wizzard
I will start with that then! Thanks to Pist-n-Broke for the PMs and the general wealth of knowledge that is the HAMB. I will keep you updated. Thanks!
Ditto, fuel pressure check. I believe the 94's like the low pressure, that Strombergs enjoy. Happy Roddin' 4TTRUK
You might check where the acc. pump arm is attached. There are 3 holes. Mine works on the middle. I use 3.5 PV. with 49 jets. Make sure your carb bases are seated to the intake with no leaks. Vac gauge on carb bases is a big help. With the adj. fuel pump you should not need more than 3 psi on the fuel side out, Having an inline fuel pressure gauge is really helpful there.
So pretty much what you said in post #4 tells you that all the parts you started with are pretty much correct, meaning jet size and Power valves, timing (advance springs). So something changed with the mileage. I would think towards inside the Dist. possibly valve adjust. Also a flat tappet cam and todays off the shelf Oil is a bad deal. The Wizzard
I don't know if Mallory has fixed their problems with the imported stuff but last time I worked on one there were so many separate issues the thing had to be rebuilt like a junkyard part...look this stuff over, maybe they are still selling the same stuff: 1. AMAZINGLY fast rubbing bloc wear...points were no no longer moving noticeably after 1,000 miles. Points were available from NAPA, curing that after two rounds. 2. Wires connecting the dual points were up against the case, close enough to leave electrical burn marks in two places but not quite enough to stop the car. 3. Very stiff advance, starting very late. (PS...other than those things, and some arcing problems with the plastic parts, it was a pretty good piece...the snaps holding the cap down seemed to be very nice.) We could not throw the thing away because the guy had built his sheetmetal right up to it and all other distributors were too big.
It's a little late...but you are simultaneously flogging 2 new carbs and a new distributor, which is a good way to go mad. You will find yourself going through the distributor when it's a carb problem, then repeat the other way. Sane way (sanity is not the hotrodder way, of course, this is just anthropological observation) is to start out with stock manifold and one carb, get carb to idle, then check out your advance and go for a ride, repeat til carb and distributor both seem happy. Swap carb, tune that one, then put on the dual setup.
So True Bruce. How about he just block off 1 of the 2 carbs with a S.S. Shim above the carb gasket below the base so he actually don't have to change the manifold? In the old days Mallory was the Cat's Ass and we loved them. Not so much anymore. However changed over to Pertronix (if your 12-V) makes me pretty happy. On my small block with tri power there isn't enough room for any stock G.M. Dist so Mallory was a must and after a few fights way to soon the electronic fix was deal. The Wizzard
I would also check fuel pressure, just to narrow things down and cross that check off your list. Especially since you mentioned running an electric pump. 94's like something like 3psi fuel pressure. Other than that the timing suggestions are a great place to start, too. I'm no gray beard and no flathead expert, but I've built several 94's over the years. Let me know if you need help (I live inner NE).
also chck your throttle shafts to make sure they are not worn causing a vacumm leak , Had this problem show up with many older carbs . replace the bushings and shaft and the a/f mixture straightened it self out .
I put in oversized and long throttle shafts, one does have ever so slight play but way better than the originals in them. I believe the fuel pressure is set at 3, but I will verify as well. Thanks for the continued input. I will get some new info as soon as I can spare some daylight to work on it!
My flat head ran like crap for the longest time. I was running similar set up with mechanical FP and 2 rebuilt 94's.... Running rich to the point where the plugs were SOAKED in fuel. After replacing everything in the ign system. testing fuel pressure countless times, and compression checks out the a$$! I finally coughed up the coin for 2 new/rebuilt 97 carbs from Unclemax here on the hamb. bolted the new carbs on. fabbed up some linkage, cleaned and dried the spark plugs and vwala! Motor runs like a top. Cant say this is your problem nor can I tell you WHAT was wrong with the 94's but I fought a rich problem with my rebuilt 94's for almost a year. It pained me, having to spend money on carbs 2wice, but I learned my lesson. I will be staying away from 94's. Good luck!
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